trent768
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Wed Mar 27, 2019 10:49 am

mandala499 wrote:
777Jet wrote:
Then the story changed. Lion Air threatened to sue the safety committee member who made the not airworthy comment. So the story changed from not-airworthy, to 'never said it was not air-worthy', after the threat to sue.

Let me explain what happened.
1.1. I heard the recording of the investigator statement, he specifically said that once the aircraft had become airborne and suffered those problems, the aircraft was deemed to no longer be airworthy and should have returned.
1.2. The local media, loving to jump to conclusion especially with their blood thirst to find a scape goat, immediately put on the headlines "aircraft was not airworthy". Yes, I received countless calls from the local media, asking for comments to their question of "how could Lion let an unairworthy aircraft depart?"
1.3. A local journalist working for a foreign media played the recording (mentioned in point 1 above), to ask exactly what it meant.
1.4. Lion Air's management was shocked to see the flood of allegation with the media claiming the NTSC had made the statement of "The aircraft was not airworthy", implying it was not airworthy prior to departure and forced it to depart.
1.5. Lion Air did make a call to NTSC. Evidence of the statement was given to Lion Air by NTSC and several credible journalists (eg: using the recording given in #3).
1.6. Lion Air agreed that NTSC did not make an erroneous statement but asked NTSC to clarify what it said. NTSC did so.
1.7. Once the aircraft was not airworthy in the air, normal convention states that it is up to the pilot on whether to continue or not. Armchair pilot syndrome has unfortunately hit mainstream media.
1.8. The aircraft kept reporting different problems. If they had 3 identical faults within 7 days, they would have grounded the aircraft. This is the "repetitive problem" methodology used after QZ8501 in 2014. Unfortunately, JT610 was the 3rd flight reporting the same problem. The engineer onboard was there to ground the aircraft at the destination or back at CGK if it had the same problem (3rd in 7 days = grounded, no matter what). Same like AF447,it was the last flight prior to having the pitot tubes changed/replaced.
1.9. How did the foreign media get it wrong? Simple, based on eyewitness statement to me: The foreign media was confused on what the NTSC said, and asked a local journo, what it meant. Of course the local journo would say, "airplane unairworthy, should not fly"... and the snowball started.
1.10. I did call one of LionAir's most senior management on points 1.4 to 1.5, which confirmed what various sources independently told me.

SheikhDjibouti wrote:
Pending confirmation from Mandala, was there anything wrong with the AFML extracts I gave to you 7 hours ago, detailing exactly what was done in Jakarta?

2.1. Am not an engineer.
2.2. I've asked several of my credible engineer and engineering analysis friends within LionAir and LionAir Group, they did what they needed to do according to the troubleshooting manual and repairs manual. There are other more detailed reports, but that is not for public disclosure (by order of the investigators), and I have not seen those either.
2.3. After several past mis-repairs (in the 737 classics days), I am told by an engineer in Lion that Boeing wanted Lion Air engineers to just follow specific instructions in the TSM and Repairs Manual, and not "get creative" on the field. I can understand why, but this limits the ability to problem solve in the field. The Engineering analysts in the office are the ones who should get creative. BUT, after QZ8501, a strict "repetitive defect" procedure is followed before you get creative. Again, pluses and minuses on each alternative.

enzo011 wrote:
Does he mean that the previous flight should not have continued when it had the same issues? Or does he mean this particular aircraft should have been grounded until it has been fixed? It was never clear for me whether it was meant that the airline missed that the aircraft itself was not safe to fly again. This was a view that was stated on this thread as well.

Then the next question was, when is it airworthy again? Who decides this? We will have to wait for the investigation if they find that the work done by the engineer on the aircraft was not to the procedure of the OEM. Either way this would have been another hole in the Swiss cheese that aligned for this flight to crash whereas the previous flight was able to continue safely.

#bangingheadontable
3.1.OK, read my reply #3119 above... or hang on... let me quote it below:
mandala499 wrote:
You misunderstood what the investigators said. Your dispatch airworthiness is only valid up to the point of the aircraft taking off. Once you develop problems in the air, to that extent, the aircraft was no longer airworthy (after it got airborne). Once you land, you can fix it to make it airworthy again.
Gotta love how all this got lost in translations (especially by non-aviations savvy journalists.

3.2. It is airworthy again once you've conducted the proper troubleshooting and repairs required on the aircraft. Then an engineer signs it off, and another engineer determines whether it should be deemed airworthy again for revenue flight.
3.3. Swiss Cheese? see 2.3. above. You can't win everything, however, you gotta continuously asses the situation to see what policies and procedures need to be changed to ensure you don't become a hostage to a previous policy decision.

Completely agree with Mandala. I followed the discussion here and read the preliminary report and were so confused when all the local online media states the exact opposite. I'm studying abroad right now so I don't have access to the proper local newspaper, which is way more credible than those clickbaity online news. I wonder how the report looks like on that one *wink wink* channel that always report the exact opposite of what happened, no matter what issues there is (y'all Indonesian know what I'm m talking about, right? Lol!).
 
osiris30
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Wed Mar 27, 2019 1:21 pm

XRAYretired wrote:
PixelFlight wrote:
osiris30 wrote:

Last comment as we are so far OT, but basically as you move down the line you get progressively further reliant on some form of electric system and if you did have a massive solar flare that fried (again, ALL) the systems you'd be pretty screwed.


Aircraft shield routinely sustain lightning strikes. The local energy density of a lightning strike event on the mechanics, electric and electronics is pretty high. A such energy density distributed by a gigantic solar flare over all exposed Earth ground surface would probably terminate our actual civilization.



Yes. Would have thought A/Cs would be at more direct risk with extremely high neutron flux density drilling holes through micro circuits than electrical induction effects. Secondarily, loss of Comms, GPS, beacons and airport landing systems would be the worry, assuming the neutron flux had not killed the crew in short order.


Ray


Well we can always go the direct emp route. Not sure the size of a strong emp device these days but it could be done in theory. Regardless the concept is more silly conjecture than serious risk launched into because a very binary statement up thread I countered with an absurdly binary statement.
I don't care what you think of my opinion. It's my opinion, so have a nice day :)
 
XRAYretired
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Wed Mar 27, 2019 1:46 pm

osiris30 wrote:
XRAYretired wrote:
PixelFlight wrote:

Aircraft shield routinely sustain lightning strikes. The local energy density of a lightning strike event on the mechanics, electric and electronics is pretty high. A such energy density distributed by a gigantic solar flare over all exposed Earth ground surface would probably terminate our actual civilization.



Yes. Would have thought A/Cs would be at more direct risk with extremely high neutron flux density drilling holes through micro circuits than electrical induction effects. Secondarily, loss of Comms, GPS, beacons and airport landing systems would be the worry, assuming the neutron flux had not killed the crew in short order.


Ray


Well we can always go the direct emp route. Not sure the size of a strong emp device these days but it could be done in theory. Regardless the concept is more silly conjecture than serious risk launched into because a very binary statement up thread I countered with an absurdly binary statement.


Just thought I'd keep the wind up going a bit longer. We could open a new thread to talk about Gamma Ray burst effects on aviation (only joking).

Ray
 
osiris30
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Wed Mar 27, 2019 2:14 pm

XRAYretired wrote:
osiris30 wrote:
XRAYretired wrote:


Yes. Would have thought A/Cs would be at more direct risk with extremely high neutron flux density drilling holes through micro circuits than electrical induction effects. Secondarily, loss of Comms, GPS, beacons and airport landing systems would be the worry, assuming the neutron flux had not killed the crew in short order.


Ray


Well we can always go the direct emp route. Not sure the size of a strong emp device these days but it could be done in theory. Regardless the concept is more silly conjecture than serious risk launched into because a very binary statement up thread I countered with an absurdly binary statement.


Just thought I'd keep the wind up going a bit longer. We could open a new thread to talk about Gamma Ray burst effects on aviation (only joking).

Ray


Honestly, it might be healthy for many on the forum to have such a lark thread. It has been pretty darned dark around here lately with 3 fatal accidents, 1 program cancellation and 1 program in trouble in the last few months. Both manufacturers are having a poor year for sales as well (the recent China order notwithstanding I believe on a book $ value Airbus is in the tank and I believe Boeing will be there by the end of April barring a major sale).
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PW100
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Wed Mar 27, 2019 5:29 pm

osiris30 wrote:
zoom321 wrote:
Air worthy or not, there is no indication from the investigation or B that Lion maintenance didn't follow B manuals. So even if indeed it was not air worthy, B is mostly to blame.


I don't think B has EVER made a statement like that about any customer, even when MX was faulty. As for the investigation, let's let it finish before we decide what it does and doesn't blame. There is no doubt MCAS will be on the list for the Lion flight, but let's see what else is.


Wel, B fairly quickly suggested Lionair maintenance issues, when they pointed out (rightly or not) that the replaced AoA instrument did not carry calibration records. Which was totally uncalled for at such stage of the investigation.
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osiris30
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Wed Mar 27, 2019 5:34 pm

PW100 wrote:
osiris30 wrote:
zoom321 wrote:
Air worthy or not, there is no indication from the investigation or B that Lion maintenance didn't follow B manuals. So even if indeed it was not air worthy, B is mostly to blame.


I don't think B has EVER made a statement like that about any customer, even when MX was faulty. As for the investigation, let's let it finish before we decide what it does and doesn't blame. There is no doubt MCAS will be on the list for the Lion flight, but let's see what else is.


Wel, B fairly quickly suggested Lionair maintenance issues, when they pointed out (rightly or not) that the replaced AoA instrument did not carry calibration records. Which was totally uncalled for at such stage of the investigation.


Was the statement true/have we seen evidence it wasn't (I ask because I haven't followed the Lion crash in NEARLY the detail I have followed the ET crash on, so things like that I have missed)? If the statement is true, why would such a statement be uncalled for?
I don't care what you think of my opinion. It's my opinion, so have a nice day :)
 
morrisond
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Wed Mar 27, 2019 8:39 pm

osiris30 wrote:
morrisond wrote:

The only reason a plane shouldn't fly normally in Total Manual mode is if you lose Thrust, lose a control surface - or all your attachments to the control surfaces are severed. If an airplane is doing something weird it's almost 100% due to electronic issues. Electronics are aids and should not be considered the primary control method.


In *totally* manual mode, every Airbus in the air today would be doomed as would the 787 and 777x (pretty sure on the last one not 100%). True FBW aircraft in totally manual mode (aka EVERY piece of electrics on the plane fried) are screwed.


Airbus has Direct Law mode (Still use the FBW controls but all limits placed on the flight envelope by the computers or software are removed) and then it also has Mechanical Back-up.

Boeing's 777 has similar systems - no idea about 787 or 777X but I would guess the same.

Good explanation here https://www.skybrary.aero/index.php/Flight_Control_Laws
 
XRAYretired
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Thu Mar 28, 2019 11:04 am

osiris30 wrote:
PW100 wrote:
osiris30 wrote:

I don't think B has EVER made a statement like that about any customer, even when MX was faulty. As for the investigation, let's let it finish before we decide what it does and doesn't blame. There is no doubt MCAS will be on the list for the Lion flight, but let's see what else is.


Wel, B fairly quickly suggested Lionair maintenance issues, when they pointed out (rightly or not) that the replaced AoA instrument did not carry calibration records. Which was totally uncalled for at such stage of the investigation.


Was the statement true/have we seen evidence it wasn't (I ask because I haven't followed the Lion crash in NEARLY the detail I have followed the ET crash on, so things like that I have missed)? If the statement is true, why would such a statement be uncalled for?

Sad I know, but I have done a wide ranging trawl and can not find any such statement from Boeing.

The only attributed statement from anyone close to the investigation re the replacement AOA sensor I can find:-

"Why the plane recorded incorrect angle-of-attack data after the sensor had been changed is not clear. Soerjanto Tjahjono, the head of Indonesia’s National Transportation Safety Committee, said that the replacement part was not new but was “serviceable” and had certification from the F.A.A. of the United States..." full article: https://www.nytimes.com/2018/11/27/worl ... rash-.html

The question of calibration of the replacement AOA when fitted seems to have come from a WSJ article and an unattributed source reported to be someone 'following' the investigation. There was further info that Boeing and the investigation team had refused to comment on the calibration of the AOA sensor.

As I understand it, there is a check test requirement on fit rather than a calibration, but there are seemingly credible ways to get the installation wrong and check test it 'correctly' accoriding to a.netters. I guess we are still TBD for cause of AOA disagree.

Ray
 
MD80Ttail
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Thu Mar 28, 2019 9:34 pm

Playing The Devil’s Advocate but in light of the fact a third jumpseating pilot was the “hero” on the penultimate flight (using the term lightly because hero’s do extra-ordinary things / this pilot, like Sully and Haynes and so many other was doing his / her job) I am surprised the discussion hasn’t turned to three person cockpits, “flight engineers” as they were known in the old days. Maybe today we need three person cockpits? Cross-trained in psychology for the suicidal pilots, flying for the incapacitated, defense against the terrorist and problems solving for emergencies??!!?

Before anyone takes me seriously I did declare to be the devils advocate. I believe a flight engineer or third pilot would only add a body to the death toll in the event things go off the rails. For an airline forum seemed like a worthy topic of discussion.
 
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PW100
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Thu Mar 28, 2019 10:42 pm

XRAYretired wrote:
osiris30 wrote:
PW100 wrote:

Wel, B fairly quickly suggested Lionair maintenance issues, when they pointed out (rightly or not) that the replaced AoA instrument did not carry calibration records. Which was totally uncalled for at such stage of the investigation.


Was the statement true/have we seen evidence it wasn't (I ask because I haven't followed the Lion crash in NEARLY the detail I have followed the ET crash on, so things like that I have missed)? If the statement is true, why would such a statement be uncalled for?

Sad I know, but I have done a wide ranging trawl and can not find any such statement from Boeing.



I meant this statement: https://boeing.mediaroom.com/news-releases-statements?item=130336

Boeing wrote:
On Oct. 28, before the flight immediately prior to Flight 610, the pilot in command and the maintenance engineer discussed the maintenance that had been performed on the aircraft. The engineer informed the pilot that the AOA sensor had been replaced and tested. The report does not include records as to the installation or calibration of the new sensor, nor does the report indicate whether the sensor was new or refurbished. Although the report states that the pilot was satisfied by the information relayed by the engineer that the AOA sensor had been replaced and tested, on the subsequent flight the pilots again experienced problems with erroneous airspeed data, and also experienced automatic nose down trim.


On review, now perhaps my words were a bit harsh, but I found it very strange that Boeing felt the need to mention any thing on the calibration of the replaced sensor in the first place.
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XRAYretired
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Thu Mar 28, 2019 11:07 pm

PW100 wrote:
XRAYretired wrote:
osiris30 wrote:

Was the statement true/have we seen evidence it wasn't (I ask because I haven't followed the Lion crash in NEARLY the detail I have followed the ET crash on, so things like that I have missed)? If the statement is true, why would such a statement be uncalled for?

Sad I know, but I have done a wide ranging trawl and can not find any such statement from Boeing.



I meant this statement: https://boeing.mediaroom.com/news-releases-statements?item=130336

Boeing wrote:
On Oct. 28, before the flight immediately prior to Flight 610, the pilot in command and the maintenance engineer discussed the maintenance that had been performed on the aircraft. The engineer informed the pilot that the AOA sensor had been replaced and tested. The report does not include records as to the installation or calibration of the new sensor, nor does the report indicate whether the sensor was new or refurbished. Although the report states that the pilot was satisfied by the information relayed by the engineer that the AOA sensor had been replaced and tested, on the subsequent flight the pilots again experienced problems with erroneous airspeed data, and also experienced automatic nose down trim.


On review, now perhaps my words were a bit harsh, but I found it very strange that Boeing felt the need to mention any thing on the calibration of the replaced sensor in the first place.


Your speculation is as good as anybody else. Lots of things are not in a preliminary report, there are no equipment inspection results at all. Boeing may have been getting a deflection of responsibility in early. The point is we don't know what the status of the replacement part was.
 
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777Jet
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Fri Mar 29, 2019 4:43 am

mandala499 wrote:
That morning, someone at Engineering Management was supposed to look at the "numerous faults over the weekend" because that hit another maintenance occurence trigger... but the plane crashed before the guy who was supposed to look at it got to the office. Sad... :(


Sad indeed...

If the first flight for that aircraft was later in the day and/or if the engineering management worker had become aware of the "numerous faults over the weekend" before the first flight that day, would that aircraft still have been allowed to operate that flight based on the work done overnight?
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mandala499
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Fri Mar 29, 2019 8:15 am

777jet wrote:
If the first flight for that aircraft was later in the day and/or if the engineering management worker had become aware of the "numerous faults over the weekend" before the first flight that day, would that aircraft still have been allowed to operate that flight based on the work done overnight?

The other trigger I meant was not a trigger for automatic grounding prior to a deeper look into the situation.
The 3 identical problem in 7 days is, however, an automatic grounding...
When losing situational awareness, pray Cumulus Granitus isn't nearby !
 
flybucky
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Fri Mar 29, 2019 9:43 am

Boeing presented the MCAS fix to pilots, regulators, and media. From https://leehamnews.com/2019/03/27/boein ... and-media/ . The article includes a screenshot of the PFD with the AOA indicator and disagree alert.

  • AOA disagree alert will be standard
  • AOA indicator will be a no cost option
  • If the AoA disagrees by more than 5.5° when the flap is retracted, MCAS will be disabled for the flight.
  • MCAS will also be disabled if the AoA Disagree displayed with the AoA differs more than 10° for over 10 seconds during flight.
  • MCAS won’t repeat if the Pilot trims during or after the MACS intervention. It will just trim once nose down for every passing of the AoA threshold.
  • MCAS can never command more stabilizer input than can be counteracted by the flight crew pulling back on the column. The pilots will continue to always have the ability to override MCAS and manually control the airplane.
 
XRAYretired
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Fri Mar 29, 2019 10:49 am

flybucky wrote:
Boeing presented the MCAS fix to pilots, regulators, and media. From https://leehamnews.com/2019/03/27/boein ... and-media/ . The article includes a screenshot of the PFD with the AOA indicator and disagree alert.

  • AOA disagree alert will be standard
  • AOA indicator will be a no cost option
  • If the AoA disagrees by more than 5.5° when the flap is retracted, MCAS will be disabled for the flight.
  • MCAS will also be disabled if the AoA Disagree displayed with the AoA differs more than 10° for over 10 seconds during flight.
  • MCAS won’t repeat if the Pilot trims during or after the MACS intervention. It will just trim once nose down for every passing of the AoA threshold.
  • MCAS can never command more stabilizer input than can be counteracted by the flight crew pulling back on the column. The pilots will continue to always have the ability to override MCAS and manually control the airplane.


My initial though was - what about dual failure high? Looking at the report , it states:-
If MCAS is activated in non-normal conditions, it will only provide one input for each elevated AOA event. There are no known or envisioned failure conditions where MCAS will provide multiple inputs.

Boeing must have addressed dual failure high in the design solution? Looking again , the further statement has:-
It will just trim once nose down for every passing of the AOA threshold. Today’s function repeated over 20 times in the Lion Air case as the pilots trimmed against a faulty AoA signal.

So suspect the new trigger is passing from an AOA value below the activation threshold to above it and therefore constant dual high will not trigger but once that can counter-acted by the pilot. Sounds goodish.

Ray
 
WIederling
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Re: What if Lion Air pilots asked ATC for outside asistance?

Fri Mar 29, 2019 11:04 am

StTim wrote:
Have we also entered the realm where it is always the pilots fault.


It has been offered here:
Boeing airplanes are so super good that a mere "pilot" can't fly them.
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Fri Mar 29, 2019 2:16 pm

Res lack of reliable news online. Seattle Times (local for Boeing), NYT, Guardian, Financial Times, WSJ (articles not editorials) Washington Post are large enough to have reporters who are skilled at aviation and have proved themselves reliable. . What European and Asian sources should I be looking at (handicap, I read and speak only English).
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WIederling
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Fri Mar 29, 2019 7:40 pm

frmrCapCadet wrote:
Res lack of reliable news online. Seattle Times (local for Boeing), NYT, Guardian, Financial Times, WSJ (articles not editorials) Washington Post are large enough to have reporters who are skilled at aviation and have proved themselves reliable. . What European and Asian sources should I be looking at (handicap, I read and speak only English).


Anything written by Dominic Gates. :-)
foreign language content : use google translate. ( amusing: take contentious topic on wikipedia
and traverse the different language versions via google translate or some other machine translator.)
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ikramerica
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Fri Mar 29, 2019 10:53 pm

XRAYretired wrote:
flybucky wrote:
Boeing presented the MCAS fix to pilots, regulators, and media. From https://leehamnews.com/2019/03/27/boein ... and-media/ . The article includes a screenshot of the PFD with the AOA indicator and disagree alert.

  • AOA disagree alert will be standard
  • AOA indicator will be a no cost option
  • If the AoA disagrees by more than 5.5° when the flap is retracted, MCAS will be disabled for the flight.
  • MCAS will also be disabled if the AoA Disagree displayed with the AoA differs more than 10° for over 10 seconds during flight.
  • MCAS won’t repeat if the Pilot trims during or after the MACS intervention. It will just trim once nose down for every passing of the AoA threshold.
  • MCAS can never command more stabilizer input than can be counteracted by the flight crew pulling back on the column. The pilots will continue to always have the ability to override MCAS and manually control the airplane.


My initial though was - what about dual failure high? Looking at the report , it states:-
If MCAS is activated in non-normal conditions, it will only provide one input for each elevated AOA event. There are no known or envisioned failure conditions where MCAS will provide multiple inputs.

Boeing must have addressed dual failure high in the design solution? Looking again , the further statement has:-
It will just trim once nose down for every passing of the AOA threshold. Today’s function repeated over 20 times in the Lion Air case as the pilots trimmed against a faulty AoA signal.

So suspect the new trigger is passing from an AOA value below the activation threshold to above it and therefore constant dual high will not trigger but once that can counter-acted by the pilot. Sounds goodish.

Ray

I was reading the German investigation into an A321 diving 4000 feet due to a double (out of 3) AoA freeze in 2015. Being a FBW system, the behavior was a tad different but the A320 also has a forced pitch down reaction to an over steep AoA (4.2) that caused a 4000ft/minute descent outside of autopilot. The only way to stop the Airbus dive was to pull back on the stick continuously to 1/2 and to eventually disable 2 (of 3) Adirus. It was NOT in the Airbus manual and took quite a while for someone on the ground to recommend that fix as a test.

In the comments, someone had mentioned that one way to detect a fault of frozen sensor is to monitor it and notice that its not fluctuating. The computer could then command a very slight alteration and test if the sensor responded. No response, immediately report the sensor as faulty.

In the lion flight, this wouldnt have worked, because the sensor was responding. But a modified logic could be applied.

1. Computer notices high AoA on sensor.
2. Out of concern for safety assume that its not lying, apply MCAS once to get the sensor below the Alpha trigger.
2a. Notify pilots of Mcas/high AoA.
3. As soon as its below safety AoA, poll opposite sensor. Check for disagree.
4. If disagree is more than 1/2 degree, disable MCAS and notify pilots of AoA/MCAS failure and let them fly the plane.

If I am understanding the chain of events correctly, that would take about 15 seconds.
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mandala499
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Sat Mar 30, 2019 6:17 am

ikramerica wrote:
In the lion flight, this wouldnt have worked, because the sensor was responding. But a modified logic could be applied.

1. Computer notices high AoA on sensor.
2. Out of concern for safety assume that its not lying, apply MCAS once to get the sensor below the Alpha trigger.
2a. Notify pilots of Mcas/high AoA.
3. As soon as its below safety AoA, poll opposite sensor. Check for disagree.
4. If disagree is more than 1/2 degree, disable MCAS and notify pilots of AoA/MCAS failure and let them fly the plane.

If I am understanding the chain of events correctly, that would take about 15 seconds.

A simpler logic is:
1. If one AOA detects above MCAS activation threshold, check the other AOA
2. If difference within acceptable threshold or of both are above MCAS activation threshold, activate MCAS.

Pre-requisites: flaps up.

---

However, a more desirable method is,
A continuous loop ADR-selfcheck... is the AOA logical for my weight, altitude, temperature and speed? If not, then self invalidate until landing.

(This already eliminate a lot of the possible false alarms.)

Then, for MCAS, you can do:
Both AOA has to be above MCAS activation threshold; or
One AOA above MCAS activation threshold and the other is within normal difference threshold; or
One AOA is above MCAS activation threshold, and yeehaa! (Although this last one is not a desirable option for obvious reasons, even with the ADR-selfchecks idea.
When losing situational awareness, pray Cumulus Granitus isn't nearby !
 
mjoelnir
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Sat Mar 30, 2019 10:17 am

I would say the best method would be, that the system would provide to the pilots the information that MCAS is active trimming. There should also be a switch, automatic trimming off, so a pilot would not need to disable electric trimming to get rid of faulty automatic trimming.

Of course MCAS should never have been dependent on one sensor only. That should get the responsible people at Boeing, the FAA and yes at EASA fired and should really have criminal consequences.

If that would be accompanied by a real difference training. The persons at Boeing that are responsible for hiding MCAS from pilots and the joke of difference training, and the persons at the FAA and EASA signing of on it, should also get fired.
 
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PixelFlight
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Sat Mar 30, 2019 10:30 am

mandala499 wrote:
However, a more desirable method is,
A continuous loop ADR-selfcheck... is the AOA logical for my weight, altitude, temperature and speed? If not, then self invalidate until landing.

In other words: flight dynamic predictive sensors filter. Can't mind why civil aircraft still don't use it. Flight dynamic models are the heart of every single flight simulator up to the very high end. Predictive filters are used in safety critical mission since Apollo. At this point this is not a "too conservative approach", but ignoring exiting proven technologies already used outside of civil aircraft ADIRU+FCC.
 
mandala499
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Sat Mar 30, 2019 5:07 pm

The ADR-SelfCheck is used at the Airbus FBW models... not sure which ones don't have it these days though.
When losing situational awareness, pray Cumulus Granitus isn't nearby !
 
flybucky
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Wed Apr 03, 2019 1:11 am

The faulty AOA sensor had been repaired at a Florida repair facility. It was on both JT043 and JT610, and was not working from the time it was installed.

A faulty sensor on a Lion Air 737 Max that’s been linked to the jetliner’s deadly crash last October and a harrowing ride the previous day was repaired in a U.S. aircraft maintenance facility before the tragedy... The repair station XTRA Aerospace Inc. in Miramar, Florida, had worked on the sensor. It was later installed on the Lion Air plane on Oct. 28 in Bali, after pilots had reported problems with instruments displaying speed and altitude. The sensor involved in the crash wasn’t working from the time it was installed, according to the NTSC’s preliminary report on the accident.

Even if it was improperly repaired or damaged in transit, the procedure for installation on the plane should catch any problems with the device, according to Charles Horning, chairman of the Department of Aviation Maintenance Science at Embry-Riddle Aeronautical University.

The sensor was made by Rosemount Aerospace Inc., of Minnesota, a subsidiary of United Technologies Corp.

https://www.bloomberg.com/news/articles ... epair-shop
 
9Patch
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Wed Apr 03, 2019 1:52 am

WIederling wrote:
zeke wrote:
95% of statistics are made up.

The correct term is "beautified" :-))

And it is a perfect fit. 95% of people have just enough understanding of statistics to demand 100% safety :-))))))))


What aircraft has ever achieved 100% safety?
 
mandala499
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Wed Apr 03, 2019 5:27 am

9Patch wrote:
What aircraft has ever achieved 100% safety?

Those who never were commercial successes comes to mind... :)
When losing situational awareness, pray Cumulus Granitus isn't nearby !
 
XRAYretired
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Wed Apr 03, 2019 7:15 am

flybucky wrote:
The faulty AOA sensor had been repaired at a Florida repair facility. It was on both JT043 and JT610, and was not working from the time it was installed.

A faulty sensor on a Lion Air 737 Max that’s been linked to the jetliner’s deadly crash last October and a harrowing ride the previous day was repaired in a U.S. aircraft maintenance facility before the tragedy... The repair station XTRA Aerospace Inc. in Miramar, Florida, had worked on the sensor. It was later installed on the Lion Air plane on Oct. 28 in Bali, after pilots had reported problems with instruments displaying speed and altitude. The sensor involved in the crash wasn’t working from the time it was installed, according to the NTSC’s preliminary report on the accident.

Even if it was improperly repaired or damaged in transit, the procedure for installation on the plane should catch any problems with the device, according to Charles Horning, chairman of the Department of Aviation Maintenance Science at Embry-Riddle Aeronautical University.

The sensor was made by Rosemount Aerospace Inc., of Minnesota, a subsidiary of United Technologies Corp.

https://www.bloomberg.com/news/articles ... epair-shop

Would suggest the report intimates they are referring to the sensor fitted immdiately prior to JT610 in place of the sensor on JT043 that would probably have been the OE fit sensor.

Ray
 
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PixelFlight
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Wed Apr 03, 2019 9:16 am

flybucky wrote:
The faulty AOA sensor had been repaired at a Florida repair facility. It was on both JT043 and JT610, and was not working from the time it was installed.

A faulty sensor on a Lion Air 737 Max that’s been linked to the jetliner’s deadly crash last October and a harrowing ride the previous day was repaired in a U.S. aircraft maintenance facility before the tragedy... The repair station XTRA Aerospace Inc. in Miramar, Florida, had worked on the sensor. It was later installed on the Lion Air plane on Oct. 28 in Bali, after pilots had reported problems with instruments displaying speed and altitude. The sensor involved in the crash wasn’t working from the time it was installed, according to the NTSC’s preliminary report on the accident.

Even if it was improperly repaired or damaged in transit, the procedure for installation on the plane should catch any problems with the device, according to Charles Horning, chairman of the Department of Aviation Maintenance Science at Embry-Riddle Aeronautical University.

The sensor was made by Rosemount Aerospace Inc., of Minnesota, a subsidiary of United Technologies Corp.

https://www.bloomberg.com/news/articles ... epair-shop

There are talking about the sensor that was flying on the JT043 + JT610 and that is still under the see floor (I don't remember reading that there recovered it from the wreckage).
But 5 months after the beginning of the analysis we still have no word about the AoA sensor failure that was replaced, not even the FDR data that is know to exists.
Adding to that the ET302 AoA sensor that is also suspected to have triggered the MCAS and this make no less that 3 AoA sensors failures without any hint about any failure mode.
Now that the scandal have splashed the Boeing safety assessment activity up to the FAA, it's maybe time to dig into the AoA sensor design.
 
flybucky
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Wed Apr 03, 2019 9:33 am

XRAYretired wrote:

flybucky wrote:
The faulty AOA sensor had been repaired at a Florida repair facility. It was on both JT043 and JT610, and was not working from the time it was installed.

Would suggest the report intimates they are referring to the sensor fitted immdiately prior to JT610 in place of the sensor on JT043 that would probably have been the OE fit sensor.

Are you saying that JT610's AOA sensor was replaced immediately prior to JT610 (Oct 29) and after JT043 (Oct 28)?

I could be wrong, but my understanding was that the AOA sensor was only replaced prior to JT043 (the Oct 28 flight before to JT610). Therefore, JT610 had the same AOA sensor had JT043.

"We know from the maintenance records for the aircraft of flights JT043 and JT610 that an installation test was done after replacing the AoA sensor before flight JT043." - https://www.satcom.guru/2019/03/taking- ... ng-on.html
 
XRAYretired
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Wed Apr 03, 2019 9:57 am

flybucky wrote:
XRAYretired wrote:

flybucky wrote:
The faulty AOA sensor had been repaired at a Florida repair facility. It was on both JT043 and JT610, and was not working from the time it was installed.

Would suggest the report intimates they are referring to the sensor fitted immdiately prior to JT610 in place of the sensor on JT043 that would probably have been the OE fit sensor.

Are you saying that JT610's AOA sensor was replaced immediately prior to JT610 (Oct 29) and after JT043 (Oct 28)?

I could be wrong, but my understanding was that the AOA sensor was only replaced prior to JT043 (the Oct 28 flight before to JT610). Therefore, JT610 had the same AOA sensor had JT043.

"We know from the maintenance records for the aircraft of flights JT043 and JT610 that an installation test was done after replacing the AoA sensor before flight JT043." - https://www.satcom.guru/2019/03/taking- ... ng-on.html

Apologies. My mistake, no excuse. As you where.

Ray
 
mandala499
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Wed Apr 03, 2019 2:59 pm

PixelFlight wrote:
There are talking about the sensor that was flying on the JT043 + JT610 and that is still under the see floor (I don't remember reading that there recovered it from the wreckage).
But 5 months after the beginning of the analysis we still have no word about the AoA sensor failure that was replaced, not even the FDR data that is know to exists.

News tricking through early this week that the AOA sensor that was replaced was defective, however no official statements yet. So far this is what is known about it: https://www.bloomberg.com/news/articles ... epair-shop
We haven't heard about the replacement that was on JT610...
When losing situational awareness, pray Cumulus Granitus isn't nearby !
 
flybucky
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Wed Apr 03, 2019 9:50 pm

PixelFlight wrote:
There are talking about the sensor that was flying on the JT043 + JT610 and that is still under the see floor (I don't remember reading that there recovered it from the wreckage).
But 5 months after the beginning of the analysis we still have no word about the AoA sensor failure that was replaced, not even the FDR data that is know to exists.

mandala499 wrote:
News tricking through early this week that the AOA sensor that was replaced was defective, however no official statements yet. So far this is what is known about it: https://www.bloomberg.com/news/articles ... epair-shop
We haven't heard about the replacement that was on JT610...

My understanding is that the article is referring to the AOA sensor that was on JT610 (as well as JT043, since they had the same sensor). I think PixelFlight is asking about the replaced AOA sensor from prior to JT043.

Here's the maintenance timeline of the last 3 flights for aircraft PK-LQP, according to the AFML in the Preliminary Report.

  • Oct 27 Manado to Denpasar - Captain's PFD no Speed and Alt indications. Speed Trim Fail light. Mach Trim Fail light.
  • -- Maintenance replaced AOA sensor. Installation test results good.
  • Oct 28 JT043 - Reported IAS and Alt Disagree. Feel Diff Press light.
  • -- Maintenance flushed Left Pitot ADM and static ADM. No change to AOA sensor.
  • Oct 29 JT610
 
aaexecplat
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Wed Apr 03, 2019 10:15 pm

Classic example of the news outlets getting the headline wrong because the details are too complicated for them...

How I read this is that JT changed the AOA sensor before JT43. And they assume it was faulty because it malfunctioned on JT43 and JT601. But they cannot have any idea whether the sensor was indeed defective or whether the ADIRU is mangling good data. They didn't even bother to check the available info that confirms JT maintenance tested the AOA sensor after install and it worked normally.

At this point, it is important we all read the full articles rather than to hang on to headlines.

Sent from my SM-G960U using Tapatalk
 
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PW100
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Thu Apr 04, 2019 3:46 pm

aaexecplat wrote:
Classic example of the news outlets getting the headline wrong because the details are too complicated for them...

How I read this is that JT changed the AOA sensor before JT43. And they assume it was faulty because it malfunctioned on JT43 and JT601. But they cannot have any idea whether the sensor was indeed defective or whether the ADIRU is mangling good data. They didn't even bother to check the available info that confirms JT maintenance tested the AOA sensor after install and it worked normally.

At this point, it is important we all read the full articles rather than to hang on to headlines.

Sent from my SM-G960U using Tapatalk


Honest question: remind me again, why was AoA sensor replacement required in first place? Could that be an indication of a sleeping problem in the system somewhere between AoA sensor and signal processor or ADIRU?
Immigration officer: "What's the purpose of your visit to the USA?" Spotter: "Shooting airliners with my Canon!"
 
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PixelFlight
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Thu Apr 04, 2019 6:47 pm

PW100 wrote:
aaexecplat wrote:
Classic example of the news outlets getting the headline wrong because the details are too complicated for them...

How I read this is that JT changed the AOA sensor before JT43. And they assume it was faulty because it malfunctioned on JT43 and JT601. But they cannot have any idea whether the sensor was indeed defective or whether the ADIRU is mangling good data. They didn't even bother to check the available info that confirms JT maintenance tested the AOA sensor after install and it worked normally.

At this point, it is important we all read the full articles rather than to hang on to headlines.

Sent from my SM-G960U using Tapatalk


Honest question: remind me again, why was AoA sensor replacement required in first place? Could that be an indication of a sleeping problem in the system somewhere between AoA sensor and signal processor or ADIRU?

Actually I don't think that anyone can remain you this: the pre-JT43 sensor is know to be at the manufacturer facility but nothing more, and his FDR data was not released to the public.
 
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litz
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Thu Apr 04, 2019 7:56 pm

PW100 wrote:
Honest question: remind me again, why was AoA sensor replacement required in first place? Could that be an indication of a sleeping problem in the system somewhere between AoA sensor and signal processor or ADIRU?


This is something that one of these final reports is going to address, for sure ...

The known is that the AoA units were replaced, presumably due to faulty data observed by the crew (or flagged by the system).

The unknown is are the things actually faulty, or is - as you noted - the issue further into the system.

LionAir's removed unit, hopefully, has been sequestered and subsequent examination will most assuredly determine it's functionality.
 
WIederling
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Fri Apr 05, 2019 8:32 am

PW100 wrote:
osiris30 wrote:
zoom321 wrote:
Air worthy or not, there is no indication from the investigation or B that Lion maintenance didn't follow B manuals. So even if indeed it was not air worthy, B is mostly to blame.


I don't think B has EVER made a statement like that about any customer, even when MX was faulty. As for the investigation, let's let it finish before we decide what it does and doesn't blame. There is no doubt MCAS will be on the list for the Lion flight, but let's see what else is.


Wel, B fairly quickly suggested Lionair maintenance issues, when they pointed out (rightly or not) that the replaced AoA instrument did not carry calibration records. Which was totally uncalled for at such stage of the investigation.


it is the small things that matter.
Boeing invests much more effort in fending of responsibility than in fixing their product properly.
Murphy is an optimist
 
XRAYretired
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Fri Apr 05, 2019 9:25 am

litz wrote:
PW100 wrote:
Honest question: remind me again, why was AoA sensor replacement required in first place? Could that be an indication of a sleeping problem in the system somewhere between AoA sensor and signal processor or ADIRU?


This is something that one of these final reports is going to address, for sure ...

The known is that the AoA units were replaced, presumably due to faulty data observed by the crew (or flagged by the system).

The unknown is are the things actually faulty, or is - as you noted - the issue further into the system.

LionAir's removed unit, hopefully, has been sequestered and subsequent examination will most assuredly determine it's functionality.

The preliminary report transcribes the maintenance log including the sensor replacement. It includes Fault log descriptions:
-Check OMF existing fault (34) found message 34-21107 (AIR DATA SIGNAL INVALID) and 34-21123 (AOA SIGNAL OUT OF RANGE). BITE ADIRS L via CDU found message 34-21023 (AOA SIGNAL FAIL). -

This sounds significantly different to what we see on JT043 and JT610 where AOA appears high but in range.

Info on the removed sensor-

https://www.nytimes.com/2019/04/02/worl ... n-air.html

"Mr. Nurcahyo, the KNKT head of air accident investigations, said that before the second to last flight, engineers replaced the left angle of attack vane because the plane had suffered problems with data readings on three previous flights. Cold temperatures, he said, appeared to have caused the sensor to malfunction.
After the crash, the replaced angle of attack sensor was shipped to Minnesota, home of Rosemount Aerospace, the Boeing subcontractor that made it, Mr. Nurcahyo said. He and other Indonesian investigators went to Minneapolis in December. The sensor, he said, was deemed defective."

This does not mean the AOA sensor on JT043 and JT610 was or was not defective. To me it looks like either an MRO error or A/C installation error.

Ray
 
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keesje
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Re: Lion Air 737MAX8 Crashed Jakarta to Pangkal Pinang

Fri Apr 05, 2019 9:30 am

In this thread we increasingly see efforts to pick out details from reports, media, posters, journalists that might not be correct, proven or unfair to Boeing. And start a big sub discussions on that, to try drift away form the evolving larger damaging realities becoming clear.

I wonder how the Lionair crash would have ended up in the history books, if the second crash wouldn't have happened and Boeing had just quietly implemented the fix. I think the media reports, denial and deflections in the months after the LionAir crash are a good indication.

:checkeredflag: The Indonesia victim family members were bought off with $40k. had to sign no claim documents. Before any investigation completed.
:checkeredflag: The MCAS problem was denied / we have to wait because no investigation completed (late 2019..) .
:checkeredflag: While denying, Boeing was fixing MCAS. Before any investigation completed.
:checkeredflag: Grounding the fleet based on all uncertainties was never considered. Because no investigation completed.
:checkeredflag: Boeing stock & stake holders were pointing out LionAir maintenance & operations records, previous incidents
:checkeredflag: Doubts were created around Lionair pilot training. Before any investigation completed.
:checkeredflag: The FAA and Boeing worked shoulder shoulder buying time, waiting for proof, fighting local authorities.
:checkeredflag: The general public / press willingly joined their preferred proud local company / authorities. Before any investigation completed.
:checkeredflag: The general public / press was much more interested in Boeing stock value and financial damage than a crash in Indonesia.
:checkeredflag: Muilenberg / Boeing Communications endlessly emphasized the excellent safety records and reputations of the Boeing company

https://sputniknews.com/science/201904041073838277-boeing-mcas-system-played-role-deadly-crashes/

:arrow: Boeing tone of voice has changed for the better over the last week. That's progress. In my opinion Boeing must now revisit their handling of the LionAir Crash & take proper action.
"Never mistake motion for action." Ernest Hemingway

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